Conventionally, a technique of displaying a screen (data) being displayed on a computer also on other computers or on a projector in the same network has been applied to various scenes such as an electronic conference. In particular, in accordance with spreading terminal devices such as tablet PCs (hereinafter also called tablet computers), there are provided various devices and applications that achieve cooperation such as an electronic conference using multiple tablet computers.
FIG. 25 is a diagram illustrating an example of the configuration of an electronic conference system 1000. As illustrated in FIG. 25, the electronic conference system 1000 includes a PC 2000, three tablet computers 3000-1 through 3000-3, and a display/projector 4000. Hereinafter, when the tablet computers 3000-1 through 3000-3 are not discriminated from one another, the tablet computers 3000-1 through 3000-3 are each referred to the tablet computer 3000.
The PC 2000 is an information processing apparatus that functions as a host (server) that carries out an electronic conference.
The PC 2000 is connected to the tablet computer 3000-1 via cables 1000a-1 and 1000b-1, to the tablet computer 3000-2 via cables 1000a-2 and 1000b-2, and to the tablet computer 3000-3 via cables 1000a-3 and 1000b-3. Furthermore, the PC 2000 is connected to a non-illustrated network such as Internet, and has a function of a Dynamic Host Configuration Protocol (DHCP) server that sets the connection of each tablet computers 3000 to the network. Hereinafter, when the cables 1000a-1 to 1000a-3 are not discriminated from one another, the cables 1000a-1 to 1000a-3 are each simply referred to as the cable 1000a; and when the cables 1000b-1 to 1000b-3 are not discriminated from one another, the cables 1000b-1 to 1000b-3 are each simply referred to as the cable 1000b. 
The PC 2000 has a function of a Web server that generates the data responsive to requests from the tablet computers 3000 and outputs the generated data to the respective tablet computers 3000.
The PC 2000 has an additional function as a file sharing server that holds files forwarded from the tablet computers 3000, such as presentation data to be used in an electric conference. The Web server may include a reference to a shared file stored in the file sharing server in a response generated in response to a request from one of the tablet computers 3000.
The PC 2000 is connected to the display/projector 4000 via a cable 1000c. The PC 2000 displays the contents of data generated by the Web server on the display/projector 4000 in response to an instruction from the tablet computer 3000.
The display/projector 4000 is a display device or a projector that reproduces the data output from the PC 2000.
The tablet computers 3000 are terminal devices that participants in an electronic conference use and each have a Universal Serial Bus (USB) terminal. Each tablet computer 3000 is connected to the PC 2000 via a Local Area Network (LAN). Here, the cables 1000a are LAN cables, and the cables 1000b are USB-to-LAN cables each having a USB terminal to be coupled to a tablet computer 3000 on one end and a LAN terminal to be coupled to the cable 1000a on the other end.
Next, description will now be made in relation to examples of the software configurations and operation of the PC 2000 and the tablet computers 3000 with reference to FIGS. 26 and 27, focusing on the function as the Web server of the PC 2000.
FIG. 26 is a diagram illustrating an example of the software configurations of the PC 2000 and the tablet computers 3000 of FIG. 25, and FIG. 27 is a diagram illustrating an example of operation of the PC 2000 and the tablet computers 3000 of FIG. 25.
As illustrated in FIG. 27, when one of the tablet computers 3000 is starting an electronic conference, the tablet computer 3000 in an user mode 3100, which is one of the operation modes of the processor of the tablet computer 3000, issues a request to start an electronic conference on a browser 3200 (step S101). In the example of FIG. 27, “GET/app/start HTTP/1.0” represents the request to start an electronic conference, and “192.168.1.2” represents the Internet Protocol (IP) address of the PC 2000, which is the destination of the request.
After the browser 3200 issues a request using a framework 3300 and a library 3400, the tablet computer 3000 in a kernel mode 3500, which is another one of the operation modes of the processor, prepares to transmit a request by the network subsystem 3600. Then, a LAN driver 3700 transmits the request to the PC 2000 via the LAN (step S102).
In the PC 2000, a LAN driver 2200 in a kernel mode 2100 receives the request and a kernel-mode network driver 2300 sends the received request to a user-mode network driver 2500 of a user mode 2400. An application 2600 of the Web server receives the request and generates a response corresponding to the Uniform Resource Identifier (URI), that is “/app/start”, of the requested data and then outputs the response (step S103). In the example of FIG. 27, the response is described in the HyperText Markup Language (HTML) format that the browsers 3200 of the tablet computers 3000 can display thereon (see <Request and Response> in FIG. 27).
The response is transmitted from the PC 2000 to the tablet computer 3000 in the reverse direction of the request (step S104). In the tablet computer 3000, the response received by the LAN driver 3700 is passed to the browser 3200 in the reverse direction of the request. Upon receipt of the request, the browser 3200 carries out displaying processing and others on the basis of the response (step S105).
When the user of the tablet computer 3000 selects a predetermined link (e.g., “ . . . /overview”) based on the response displayed on the browser 3200, the browser 3200 issues a request to the selected link. In this manner, the tablet computer 3000 repeats the procedure of S101 to S105.
The procedure of steps S101 to S105 is carried out between the PC 2000 and the respective tablet computers 3000-1 to 3000-3 independently from one another. Accordingly, during an electronic conference, the respective users refer to the same screen provided by the PC 2000 (Web server), which is exemplified a screen displaying by the presentation material of the current speaker, through their own tablet computers 3000. One of the tablet computers 3000 is allowed to instruct the PC 2000 to switch the screen (e.g. presentation material) to be displayed on the display/projector 4000.
As illustrated in FIGS. 25-27, the electronic conference system 1000 allows the tablet computers 3000 to refer to the same screen as that of the PC 2000 (Web server), so that the electronic conference can be held.
A known related art achieves the screen mirroring function of the PC by a file system (a Hard Disk Drive (HDD) and a memory) of a small box connected to multiple PCs via a connection interface such as USB and the Operating Systems (OSs) of the PCs (e.g., Patent Literature 1).
Another known related technique is an application for electronic conferences and presentations using the Wireless Fidelity (Wi-Fi) communication function (e.g., Non-Patent Literature 1 or Non-Patent Literature 2). In this technique, the tablet computer of the host connected to Wi-Fi starts the electronic conference. After that, tablet computers connected to the same Wi-Fi participates in the electronic conference and downloads the conference material from the tablet computer of the host. In this technique, when the page of the conference material forwarded on the tablet computer of the current speaker, the page of the conference material being displayed on the remaining tablet computers are also automatically forwarded.
[Patent Literature 1] Japanese Laid-open Patent Publication No. 2005-92751
[Non-Patent Literature 1] RICOH, “Releasing Application “RICOH TAMAGO Presenter” for paperless conference and presentation using iPad” (online) May 19, 2011, (retrieved) Apr. 20, 2012 in Internet, URL: “www.ricoh.co.jp/info/110519.html”
[Non-Patent Literature 2] RICOH, “RICOH TAMAGO Presenter”, (retrieved) Apr. 20, 2012 in Internet, URL: “www.ricoh.co.jp/software/tamago/presenter/”
The electronic conference system 1000 of FIG. 25 may have inconvenience due to the following constrains (i) to (iii) when being put into practice.
(i) For the security reason, the browser 3000a may be prohibited from uploading files onto the PC 2000. In this case, the tablet computers 3000 upload files to the PC 2000 (file sharing server) using a predetermined application. However, some specifications of tablet computers 3000 do not simultaneously run the browser 3200 and such application.
(ii) The PC 2000 is incapable of accessing files stored in a tablet computer 3000 through the LAN.
(iii) If the OS of the tablet computer 3000 is an Android (trademark) OS, the specification of the OS prevents the tablet computer 3000 from connecting to an ad-hoc network, that is, to the PC 2000.
Carrying out screen mirroring among the multiple PCs using the small box, the above related technique preferably includes high-speed communication function and high-performance hardware for the small box and the PCs. For the above, the related technique may have a difficulty in conducting an electronic conference using devices and environment already exist. This means that additional cost is entailed in order to introduce equipment for the electronic conference.
Furthermore, the other related technique enables multiple tablet computers connected via Wi-Fi to refer to the same files. This technique allows each tablet computer to access an external network, such as Internet or Intranet of a company via one or more access points. This involves security risks such as leaking the presentation material to the third party and invading Intranet through the tablet computers.
The above respective techniques may involve various problems due to communication manners between a tablet computer and a PC and among tablet computers. These problems hinder introduction and execution of an electronic conference using multiple tablet computers or reduce security.
The above description assumes that an electronic conference is held using multiple tablet computers, but is not limited to this. Various kind of cooperation carried out with multiple terminal devices involves the same problems.